1. Field of the Invention
The present invention relates to a recording tape cartridge. The recording tape cartridge accommodates a single reel around which a recording tape, such as a magnetic tape, primarily used as a recording/playback medium for a computer or the like.
2. Description of the Related Art
Conventionally, there is known a magnetic tape cartridge constructed such that a magnetic tape used as a data recording/playback medium for a computer or the like is wound on a single reel, and the reel is accommodated in an accommodating case. A leader member, such as a leader pin, a leader tape, or a leader block, is provided to the end of the magnetic tape. The leader member is pulled out from an opening of the magnetic tape cartridge by using pull-out means provided in a drive device, and the magnetic tape fixed to the leader member is wound around a take-up reel in the drive device.
A reel gear is formed annular in the center of the reel lower surface appearing from an opening formed on a lower surface of the magnetic tape cartridge, a drive gear provided on a rotation shaft in the drive device is engaged with the reel gear, and the reel is thereby rotationally driven. Therefore, data can be recorded on the magnetic tape, or data recorded on the magnetic tape can be played back in such a manner that the reel of the magnetic tape cartridge and the take-up reel of the drive device are rotated in synchronization.
Magnetic tape cartridges of the above-described type are characterized in that the accommodating space for preservation can be small, and a large amount of information can be recorded. The position of the opening and the type of a door for opening and closing an opening are different depending on the type of the leader member. More specifically, as shown in FIG. 7, with a leader pin 70, an opening 68 is formed on a sidewall 64 of an accommodating case formed parallel to the direction of insertion to the drive device (direction of an arrow P). In this case, a door 66 slidably moves in the same direction as the direction of insertion to thereby open and close the opening 68.
This type of door 66 is assembled into the case 60 by a coil spring 67 being placed on a shaft 65 projecting from a rear end portion of the door 66, and the rear end portion of the coil spring 67 being anchored on an anchor portion 63 provided at the case 60. An engagement portion 69, which is engaged by an unillustrated opening/closing member provided at the drive device, projects outwardly at the front end portion of the door 66.
Accordingly, when the magnetic tape cartridge is loaded into a drive device, the opening/closing member engages the engagement portion 69, the door 66 is pushed relatively rearward against the urging force of the coil spring 67, and the opening 68 is opened. At this time, a cut-out portion 61 for exposing the engagement portion 69 is formed at a side wall 62 side which faces the drive device and at an end portion at the opening 68 side, so that the opening/closing member can suitably engage with the engagement portion 69.
However, when the cut-out portion 61 is formed at the opening 68 side end portion of the side wall 62 in this way, when the opening 68 is closed by the door 66 such as when the magnetic tape cartridge is not being used (is not inserted in a drive device, or is being stored or transported) or the like, there is the concern that dust and the like may enter in from the gap between the cut-out portion 61 and the engagement portion 69.